The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
In many situations, there is a need for a shooter to be able to track the movement of a successfully-impacted target. For a hunter, it may be necessary to track an animal after it has been shot from a safe distance until it stops moving and is retrievable. In military environments, tracking the movements of an impacted enemy vehicle or wounded enemy combatant can lead to the discovery of the locations of hidden enemy installations.
The need to track the location of ordnance after firing and impact has led to the integration of location-tracking systems (e.g., GPS transmitters, etc.) into ordnance. The ordnance must also include a power source, such as a battery, for the location-tracking system to work.
Ordnance can often be stored for long periods of time before being used and, as such, systems that used a battery already electrically coupled with the location-tracking hardware suffered from battery draw occurring during storage. Even if the location-tracking hardware is not active while the ordnance is in storage, the electrical connection with the battery will cause a slow, steady draw of battery power.
Others have tried to overcome this problem by delaying the closing of the circuit between the battery and location-tracking hardware until the deployment of the ordnance. However, the existing solutions have required complicated mechanisms to work. The complexities of these existing systems carry an increased risk of failure. Additionally, the complexity of the internal components of existing tracking ordnance systems is difficult to scale down to smaller types of ammunition such as bullets.
U.S. Pat. No. 8,007,934 to Glaathar discusses a mortar where an ampoule is filled with an electrolyte that, when the ampoule is punctured, the electrolyte is released to contact battery cells to generate electrical voltage. However, the use of a liquid electrolyte requires a complicated mechanism for the storage and proper release into contact with the battery cells to generate the electrical power. Additionally, because the electrolyte is a liquid, there is a risk of malfunction due to a premature puncturing of the ampoule or an internal or external leak of the electrolyte during the firing of the mortar or the impact of the mortar.
U.S. Pat. No. 3,754,996 to Snyder also uses a liquid electrolyte that is caused by the centrifugal force of the spinning shell to flow into spaces to complete the electrical circuit. Snyder is silent as to the components of the shell requiring a power supply. However, the system of Snyder would only work to power the shell during flight as upon impact, the rotation holding the liquid electrolyte in place would cease, allowing the electrolyte to flow out of the spaces and thus disrupting the electrical circuit.
U.S. Pat. No. 5,381,445 to Hershey discusses a cartridge where the battery is held apart from an electrical contact by a spacer that, when the cartridge is fired, is crushed by the battery such that the battery comes into contact with the electrical contact to complete the circuit. However, the system in Hershey requires a biasing spring to hold the battery against the contact after firing. This means that, upon impact, the deceleration could cause the spring to compress and thus the battery to become disconnected from the electrical contact. Additionally, if the spring is damaged in any way during impact, the system would fail.
Other systems, such as the one in U.S. Pat. No. 6,650,283 to Bridges discuss triggering mechanisms such as switches that turn on the electronic components. However, in these systems, the circuit is already completed and as such, the battery is slowly drained even during storage.
Other existing systems have required an external modification to the ordnance for the tracking ordnance to function. These external modifications to the ordnance can negatively influence the flight characteristics such that they behave differently from and inferior to ordinary ordnance.
Still other existing tracking systems have required a modification to the weapon firing the tracking ordnance for the system to properly function. Thus, the tracking ordnance is no longer usable in ordinary weapons. These modifications can affect the normal function of the weapon, require additional training to personnel, and are expensive to implement in the numbers typically required by a military unit or organization.
Thus, there is still a need for improved tracking ordnance that reduces the complexity of the power supply components such that it can be easily scaled down to small-caliber bullets, increases the reliability of the tracking system, and can be used along with ordinary ordnance without requiring modifications to the weapons.